<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script>
			/* 需求： 在页面加载完成以后，过3秒将div扩大为原来的4倍 */
			window.onload = function(){
				
				window.setTimeout(function(){
					
					var divObj = document.getElementsByTagName("div") ;
					 
					var height = divObj.style.height ; 
					var width = divObj.style.width ; 
					
					height = window.parseInt(height) ;
					width = window.parseInt(width) ;
					
					height = height * 4  ;
					width = width * 4 ; 
					
					divObj.style.height =  height + "px" ;
					divObj.style.width =  width + "4px" ; 
					
				} , 3000) ;
				
				
			} ; 
			
		</script>
	</head>
	<body>
		
		<div style="border: 1px solid red ; height: 100px; width:100px; background-color: green ;">
			
			
		</div>
		
		
	</body>
</html>
